Separating device

ABSTRACT

The invention relates to a separating device, in particular in the manner of a spiral separator (10), for the separation of impurities, particularly in the form of solids, from a gaseous medium flow, such as air, which can be fed to a spiral-shaped guiding device (42) and thus brings about an at least partial separation of the respective impurities from the medium flow. The invention is characterized in that the guiding device (42) has a plurality of spiral arms (44) which delimit radially extending flow spaces (46) and which are arranged in an adjacent manner opposite to one another such that the medium flow is guided radially outwards.

The invention concerns a separating device, in particular in the manner of a spiral separator, for the separation of solids from a gaseous medium flow, which may be fed into a spiral-shaped guiding device.

The document DE 10 2010 014 278 A1 discloses a cyclone separator for the separation of liquid and/or solid particles from a gaseous flow, comprising a first cyclone component with at least one, essentially cylindrical, cell pipe that is provided with a guiding device, which may be used to cause the gas flow to go into rotation for the purpose of separating the particles. Moreover, the known solution is provided with a particle outlet to discharge the separated particles from the device, as well as a second cyclone component, disposed subsequently in flow direction of the gas flow, with at least one immersion pipe that is contained inside the cell pipe, and which is at least partially attached to the downstream end of the cell pipe, following the flow direction of the gas stream, as well as a central outlet for discharging the cleaned gas flow.

Said known cyclone separator is advantageously made in form of a so-called multicell cyclone in which the first cyclone component is provided with a plurality of cell pipes and the second cyclone component is provided with a plurality of immersion pipes. Due to the multicell cyclone design of the known solution it is possible to separate the respective solids from the gaseous medium flow with a high degree of efficiency; nevertheless, this design is complex in implementation and thus expensive.

The document EP 2 471 588 A1 discloses a further device for the separation of liquids from gaseous media, comprising a device container with a gas inlet and a gas outlet as well as a separating element, in particular in form of an air/oil separator, which is disposed in the flow path between gas inlet and gas outlet. This known solution uses a spiral separator with only one spiral arm in form of a spiral-shaped flow container that is disposed between the gas inlet and the separating element, wherein said spiral separator subdivides the container into an upper chamber and a lower chamber.

The known device avoids turbulence inside the flowing medium during operation and facilitates a compact design; nevertheless, the known solution is lacking with respect to its separating performance in removing liquid as contaminant from the flow of gaseous media.

Based upon said prior art it is the object of the invention to further improve the known solutions in such a way that a separating device is provided that saves on installation space, can be implemented cost-effectively and still performs reliably in operation at a high degree of separation.

Said object is met by a separating device with the characteristics of claim 1 in its entirety.

Due to the fact that, according to the characterizing part of claim 1, the spiral-shaped guiding device for the medium flow is provided with a plurality of individual spiral arms, which are arranged in adjacent pairs and delimit radially extending flow spaces located opposite to each other in such a way that the medium flow is directed outwards, a high degree of separation of contaminants from the gaseous medium flow is achieved in a functionally reliable manner because of the plurality of fixed, spiral-shaped guide vanes of the spiral separator; moreover, the spiral separator can be produced in a cost-effective and space-saving manner. This has no equivalent in the prior art.

In a preferred embodiment of the separating device according to the invention it is provided that the medium flow, which is present particularly in form of a gas stream contaminated with solid particles, such as dust-laden, surrounding air, is supplied via a medium inlet of a housing of the device, axial to a central area of the guiding device, in which the individual spiral arms of the guiding device meet. In particular where the medium inlet opening gradually reduces in the direction of the guiding device, the medium flow can initially be sped up prior to a uniform distribution into the distribution chambers of the spiral separator, which is delimited by the spiral arms, which is favourable for the further acceleration via the spiral-shaped vanes of the guiding device in radial direction when viewed outwards.

In a particularly preferred embodiment of the separating device according to the invention provision is made that at least some of the spiral arms used for the guiding device, but preferably all spiral arms, are arranged in adjacent pairs which delimit flow spaces, the progression of which from a central section of the guiding device is either diverging towards the outside, converging or is essentially constant where the spiral arms extend parallel to each other. Through the described arrangement of the individual spiral arms, that is, diverging, converging or parallel, the flow velocity may be reduced, accelerated or maintained essentially constant by means of the guiding device. This has no parallel in the prior art.

In a further preferred embodiment of the separating device according to the invention, the spiral separator is surrounded by a housing with a predeterminable, radial gap so that, due to the spiral-shaped flow of the medium, which is caused by the spiral arms of the guiding device, the contaminants separated from the medium flow, such as solids, are able to precipitate on the inside of said housing. Apart from the solids contamination already discussed, it is also possible to precipitate drops of liquid, such as condensate (water) etc. from the gas stream.

In a further particularly preferred embodiment of the separating device according to the invention it is provided that the respective spiral arms of the guiding device follow the curve of a so-called Fibonacci spiral at least outside of its common, inner joining section. Thus, a kind of golden section is achieved for the spiral shape of each spiral arm, which has a most favourable effect on the energetic flow control of the medium flow.

In a further preferred embodiment of the separating device according to the invention provision is made that all spiral arms of the guiding device are the same, in particular that they have the same length and the same height, so that the thus rotationally symmetrical spiral separator can be disposed inside the housing of the separating device in any desired installation direction in longitudinal direction. Moreover, such a spiral separator with its fixed spiral arms that form the guide vanes of the guiding device can be produced cost-effectively, for example, as an injection-moulded plastic component. Due to the symmetrical design of the spiral separator an equally good discharge rate is achieved for the medium flow as well as for the desired separation rate in every direction of the spiral separator.

In a further particularly preferred embodiment of the separating device according to the invention it is, moreover, provided that the spiral-shaped guiding device is made in form of a pre-separator that is followed at least in downstream direction of the medium flow by an air filtration system. Any solids contamination, especially in form of particulate contamination, that has not yet precipitated from the medium flow, can be reliably removed in this manner by the filter medium used, prior to conveying the air-gas flow from the separating device to the respective combustion chamber of a combustion engine for which the separating device according to the invention undertakes the air filtration process.

The air filtration system may preferably be provided with a main filter element with greater filter fineness and a safety filter element with reduced filter fineness that is disposed concentrically inside the main filter element or which is located downstream. In the instance that said air filter element in form of the main filter element has to be replaced with a new element once it has been subjected to particulate contamination, and the main filter element is accidentally left out during the intended exchange, the safety filter element would perform a sufficiently high level of separation of any remaining particulate contamination in the operation of the separating device without causing any damage to the combustion engine.

Because the medium flow, which has been cleaned from any solids, exits the device housing after passing through the air filtration system via a medium outlet, which is disposed coaxial to the medium inlet in the same housing, wherein the combustion engine that is connected to the separating device, moves the medium or gas flow, seen in axial direction, in an accelerated manner through suction from the air inlet to the air outlet in axial direction through the device housing, the axial flow is superimposed by the radial air stream of the spiral pre-separator so that overall, starting with the spiral pre-separator, idealised an even, spiral-shaped medium flow forms inside the device housing, in particular along its inner wall, thus achieving in an energetically particularly advantageous manner a flow through the separating device as a whole. The said spiral-shaped medium flow is also advantageous because the main filter element, which extends in axial direction inside the device housing, is also evenly surrounded by a spiral-shaped flow, so that in this manner the particulate contamination still remaining in the medium flow is uniformly separated through the filter medium of the main filter element. In this way the main filter element is uniformly loaded with the particulate contamination and is thus available for a long service life. In summary, the device is continuously supplied through a medium inlet with a stream of more or less contaminated medium, which is cleaned by means of spiral pre-separator and filter system and delivered to a medium outlet, to which the suction side of the combustion engine with its combustion chambers is connected.

Since the device housing is provided, besides the medium inlet and outlet, with at least one further opening for the discharge of the precipitated solids, the solid contaminants cab be easily discharged from the separating device into the environment. The respective discharge opening may be provided with a closable discharge valve to be able to discharge the contaminants from the separating device in batches or continually. Within the scope of the described air filtration for the combustion engine, the particulate solids contamination is usually dust from the surrounding air in which the combustion engine is used, for example for driving a machine.

The housing may preferably be made from multiple parts, preferably housing parts that can be detached from each other, wherein the spiral-shaped guiding device is preferably disposed in one housing part and the above-described filter system in the other housing part. It is thus possible to separate the individual housing parts from each other when required, wherein the one housing part with the filter system may remain on the combustion engine to facilitate the exchange of filter elements, in particular the exchange of the main air filter element for a new element.

The separating device according to the invention will now be described in greater detail by way of an exemplary embodiment shown in the drawing. Shown are diagrammatically only and not to scale in:

FIG. 1 the separating device as a whole by way of an assembly drawing;

FIG. 2 a perspective plan view of the spiral separator according to FIG. 1;

FIGS. 3 and 4 a plan view of the end face of the spiral separator according to FIG. 2, once with diverging spiral arms that are facing anticlockwise, and once in clockwise direction;

FIG. 5 the design of a spiral arm as so-called Fibonacci spiral for the spiral separator according to the FIGS. 2 to 4; and

FIGS. 6 and 7 a depiction corresponding to that of FIG. 4 with converging and respectively parallel to each other arranged spiral arms.

The separating device shown in FIG. 1 shows as pre-separator a spiral separator 10, attached to which, in flow direction of a medium, in particular in form of a gas or air stream, is an air filtration system 12 comprising a main filter element 14 and a safety filter element 16. The main filter element 14 takes the form of a hollow cylinder and is comprised of a filter medium with greater filter fineness. The main filter element 14 is able to house the safety filter element 16 concentrically inside it, which in turn also takes the form of a hollow cylinder, but its filter medium is of a lesser filter fineness compared to that of the main filter element 14. Both filter elements 14, 16 may be disposed inside a pot-shaped lower housing part 18. To facilitate this, the lower housing part 18 is provided with an integrated connection socket 20 to connect to the end of the main filter element 14, as well as a further integrated socket 22 to connect to the one end of the safety filter element 16, wherein each of the filter elements is secured to the socket-shaped connectors 20, 22 in a sealing manner. Provided at the bottom of the pot-shaped lower housing part 18 is a socket-shaped medium outlet 24, which supplies the clean air generated by the separating device to a commonly used combustion engine (not shown) of a machine or some other kind of vehicle. Instead of the combustion engine it is also possible to clean compressor air using the separating device.

When viewing FIG. 1, a further outlet opening 26 is provided adjacent to the medium outlet 24 at the bottom end, extending at an angle, which is provided as means to discharge the solid contaminants from the separating device; the outlet opening 26 facilitates in particular the dust discharge from the air into the environment. To facilitate the dust discharge via the socket-shaped outlet opening 26 from the lower housing part 18, said outlet opening 26 may be connected to an exhaust system of the combustion engine (not shown in detail), which generates a vacuum when the combustion engine is in operation, which facilitates the dust discharge from the outlet opening 26. To help avoid the undesired introduction of contaminants or moisture from the environment into the inside of the lower housing part 18, the outlet opening 26 may be provided with a dust discharge valve (not shown), in particular of the type of a spring-loaded non-return valve, which opens under the suction effect of the exhaust system in the direction of the free opening cross-section of the outlet opening 26 when the device and the combustion engine are in operation, and closes towards the inside of the lower housing part 18, for example when the combustion engine has stopped.

The already introduced spiral separator 10 is disposed in a lid-shaped upper housing part 28, the inside of which surrounds the outer circumference of the spiral separator 10 at a predeterminable distance. The lower housing part 18 together with the upper housing part 28 forms the complete housing 30 of the separating device. Moreover, it is in the usual manner possible to attach the upper housing part 28 in a detachable manner to the lower housing part 18 via toggle type fasteners 32, of which only one fastener is shown in FIG. 1. When installing the separating device in an overall air supply system or exhaust system it is to be expected that the lower housing part 18 is located and attached in the vicinity of the not-depicted combustion engine and remains there when filter elements are exchanged.

The complete housing 30 will be opened in particular if the contaminated main filter element 14 has to be replaced with a new element. The already described safety filter element 16 may remain in its socket-shaped connector 22 in the lower housing part 18, so that in the instance that the new main filter element 14 is inadvertently not installed, the separation process with the device is still possible because the safety filter element 16 still separates particulate contaminants from the medium gas stream, even in the instance where it was overlooked to insert the new main filter element 14. Thus the remaining safety filter element 16 prevents in any case that any contaminated air damages the combustion engine that is connected to the separating device.

On the side that faces the main filter element 14, the spiral separator 10 is also provided with a pot-shaped connector 34, into which the main filter element 14 can be inserted in a sealing manner with the end that faces the spiral separator 10. Moreover, the spiral separator 10 is attached to the upper housing part 28 via three through-bolts 36 that pass from the free end face through said upper housing part 28. Each of the fastening points is depicted in dashed lines in FIG. 1. Furthermore, the upper housing part 28 is provided with a medium inlet 38 in form of a hollow socket on the free end face that points outwards.

Thus the medium or air intake takes place via the medium inlet 38 of the upper housing part 28, wherein the air intake follows the depicted arrow in axial direction to the longitudinal axis of the overall separating device. Due to the spiral separator 10 the axial air intake is transformed into a rotational movement towards the outside, and the superimposition of said rotational air movement with the axial intake flow of the air via the medium inlet 38 causes the spiral-shaped movement of the medium or air stream along the spiral track 40 to move to the inner wall of the complete housing 30. In order to ensure an undisturbed spiral track path 40 for the air stream, the spiral separator 10 as well as the main filter element 14 is provided, in radial direction, with a predeterminable distance to the upper housing part 28 and to the lower housing part 18 respectively. If the air stream in question contains particulate contamination, such as dust, the air laden with dust is accelerated through the depicted spiral track 40 and the air is directed along the inner wall of the complete housing 30 in the direction of the medium outlet 24, wherein the solid contaminant in form of said dust is slowed down through friction on the inside wall of the complete housing 30 and is then discharged via the dust discharge valve (not shown) from the outlet opening 26 from the complete housing 30, preferably into the exhaust gas system of the vehicle. The remaining air is then cleaned further through the main filter element 14 and ends up in form of clean air via the medium outlet 24 at the combustion chambers of the connected combustion engine.

The FIG. 2 depicts the end face of the spiral separator 10 in perspective view. The spiral separator 10 is provided with a spiral guiding device 42 in form of individual spiral arms 44, which are located on the end surface of the pot-shaped connector 34 disposed underneath, which is provided for the main filter element 14. This may be designed as a single piece; the cylindrical connector part 34 may in particular be produced in form of an injection-moulded part in one piece together with the spiral guiding device 42 with the individual spiral arms 44. As is particularly apparent from the end views in FIGS. 3 and 4, the individual spiral arms 44, which are arranged in adjacent pairs, delimit radially outwards expanding flow spaces 46, located opposite to each other, which guide the medium or air stream radially from the inside to the outside. Said guidance of the air may take place, accelerating from inside to the outside via the radially expanding flow spaces 46.

The individual spiral arms 44 converge inwards to a common area 48, and the raw air or surrounding air, which contains more or less dust and which is supplied axially via the medium inlet 38, impacts on the cylindrical plate that forms the common area 48, from where it is evenly distributed into the flow spaces 46 and is moved radially outwards. As is also shown in FIG. 2, respective spiral arms 44 are provided with evenly spaced threads 50 for engagement with the respective through-bolts 36 to facilitate the mounting of the spiral guiding device 42 on the lid-shaped upper housing part 28, which then forms the spiral separator 10.

As is particularly apparent from FIGS. 3 and 4, the spiral arms 44 may be disposed on the pot-shaped connector 34 as left-rotating or right-rotating. Moreover, all spiral arms 44 end with their free end flush at the common plane of the cylindrical outer circumference of the pot-shaped connector 34. If, for example, the medium inlet 38 is provided with an acceleration section that conically reduces in the direction of the spiral separator 10, the air that is aspirated in an accelerated manner by the combustion engine via the medium outlet 24 can then strike, correspondingly accelerated, the common connection area 48 of the spiral separator 10 at the inlet side so as to receive an initial acceleration, which is advantageous for the discharge behaviour of the particulate contamination from the medium stream. The volume quantity of the gas or air stream that is to be accelerated by means of the spiral separator 10 is adjustable not only through the size of the intake opening, that is, the medium inlet 38, but also via the axial height of the vane-shaped spiral arms 44 of the spiral guiding device 42. The speed of the medium or gas flow on the other hand is determined by the number of spiral arms 44 as well as their length 52 which, according to the depiction in FIG. 5 results from the design of the respective spiral arm 44 in the shape of a Fibonacci spiral, in which the so-called golden section is implemented in the design. Since the spiral arms 44, with their ends that face each other, end in a common area 48, not the entire Fibonacci spiral is realised towards the inside.

As the diagrams according to FIGS. 2 to 4 show, the individual spiral arms 44 are arranged divergent, that is, starting from the central connection area 48, the individual flow spaces 46 expand, each of which is bounded by pairs of spiral arms 44 from inside to outside so that in this manner the flow speed is reduced in that direction provided that the application, which is dependent on the particulate contamination, stipulates this. In a converging arrangement of the spiral arms 44 on the other hand, as shown in FIG. 5, the flow spaces 46 can reduce in outward direction starting from the centre section 48, which results in an increase in flow speed from inside to outside. In the embodiment according to FIG. 6, on the other hand, the individual spiral arms 44 are arranged essentially parallel to each other in pairs, so that the flow spaces 46 from inside to outside remain constant, which also results in a constant flow velocity.

The cylindrical extension of the spiral separator 10 in form of the pot-shaped connector 34, following the individual spiral arms 44 or spiral vanes, facilitates the radial guidance of the solids-contaminated gas or air stream in longitudinal direction of the cylindrical inner wall of the complete housing 30. Due to the volumetric difference resulting from this, the precipitation of the solids is usually in form of dust from the gas/air stream, wherein the solids are transported along the inside of the housing wall up to the accumulation point in form of the discharge opening 26 in housing 30 and are disposed from there into the environment. The spiral separator 10 according to the invention may be utilised as pre-separator in the described air filtration system 12, followed by a radially or axially sealing filter element, in particular in form of the main filter element 14 where dirt particles such as dust flow around it inside housing 30, and air flows through said filter element respectively. This results in a complete separation of the particles/gas mixture, and clean air can be fed via the medium outlet 24 of housing 30 into the combustion chambers of the combustion engine. 

1. A separating device, in particular in form of a spiral separator (10), for separating contaminants, in particular in form of solids, from a gaseous medium stream, such as air, that may be fed into a spiral-shaped guiding device (42), thus causing an at least partial separation of contaminants from the medium flow, characterized in that the guiding device (42) is provided with a plurality of spiral arms (44) which are arranged in adjacent pairs and delimit radially extending flow spaces (46) located opposite to each other in such a way that the medium flow is directed outwards.
 2. The separating device according to claim 1, characterized in that the medium flow is supplied via a medium inlet (38) of a housing (30) of the device, axial to a central area (48) of the guiding device (42), in which the individual spiral arms (44) meet.
 3. The separating device according to claim 1, characterized in that at least some of the spiral arms (44) used for the guiding device (42), but preferably all spiral arms (44), are arranged in adjacent pairs which delimit flow spaces (46), the progression of which from a central section (48) of the guiding device (42) is either diverging towards the outside, converging or essentially constant where the spiral arms (44) extend parallel to each other.
 4. The separating device according to claim 1, characterized in that the individual spiral arms (44) converge inwards to a common area (48), and the raw air and/or surrounding air is supplied axially via the medium inlet (38) and impacts on the cylindrical plate that forms the common area (48), from where it is evenly distributed into the flow spaces (46) and is moved radially outwards.
 5. The separating device according to claim 1, characterized in that, due to the spiral-shaped (40) medium flow, which is caused by the spiral arms (44) of the guiding device (42), the solids precipitate on the inside of the housing (30).
 6. The separating device according to claim 1, characterized in that the respective spiral arms (44) of the guiding device (42) follow the curve of a Fibonacci spiral at least outside of its common joining section (48).
 7. The separating device according to claim 1, characterized in that all spiral arms (44) of the guiding device (42) are the same, in particular that they have the same length and the same height.
 8. The separating device according to claim 1, characterized in that the guiding device (42) is made in form of a pre-separator (10) that is followed at least in downstream direction of the medium flow by an air filtration system (12).
 9. The separating device according to claim 1, characterized in that, seen in the direction of the medium flow, a safety filter element (16) with reduced filter fineness is disposed upstream of a main filter element (14) with greater filter fineness.
 10. The separating device according to claim 1, characterized in that the medium flow, which has been cleaned from any solids, such as dust, exits the housing (30) after passing through the air filtration system (12) via a medium outlet (24), which is disposed coaxial to the medium inlet (38) in housing (30).
 11. The separating device according to claim 1, characterized in that the housing (30) is provided with at least one further opening (26) for the discharge of the precipitated solids.
 12. The separating device according to claim 1, characterized in that the housing (30) is preferably made from multiple parts, preferably housing parts (18, 28) that can be detached from each other, one for the air filtration system (12) and the other for the guiding device (42). 